Today, reminder - CMSP Seminar (Atomistic Simulation Webinar Series): Wednesday 15 December 2021 at 11 a.m.

[CMSP Seminars Secretariat]

Virtual - Zoom Meeting

CMSP Atomistic Simulation Webinar Series
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* * * *Wednesday, 15 December 2021 at 11:00 a.m.** * *

Speaker: *Iurii Timrov***- Theory and Simulation of Materials (THEOS) 
and National Centre for Computational Design and Discovery of Novel 
Materials (MARVEL), École Polytechnique Fédérale de Lausanne (EPFL), 
Lausanne, Switzerland

Title: Density-functional theory with extended Hubbard functionals: 
recent developments and applications

Register in advance at:
https://zoom.us/meeting/register/tJEvc-CurjIuHdLM4eP8EkyEcQ4TRUr8-nsv
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information about joining the seminar.


Abstract:

Density-functional theory (DFT) with extended Hubbard functionals is a 
powerful method for studying complex materials containing 
transition-metal and rare-earth elements, owing to its accuracy in 
correcting self-interactions and its low computational costs [1]. There 
are two key elements in these formulations which are closely 
interconnected: i) the choice of the on-site U and inter-site V Hubbard 
parameters, and ii) the choice of the Hubbard manifold. Recently, we 
developed an automated and reliable approach for the first-principles 
determination of U and V using density-functional perturbation theory 
(DFPT) [2,3]. In this talk I will show that DFPT allows us to reduce 
significantly computational costs, improve numerical accuracy, and fully 
automate the calculation of the Hubbard parameters by recasting the 
linear response of a localized perturbation in supercells into an array 
of monochromatic perturbations that can be calculated in the primitive 
cell. This framework can be used with different Hubbard manifolds, such 
as nonorthogonalized and orthogonalized atomic orbitals, including the 
respective calculation of Pulay (Hubbard) forces and stresses [4] that 
are needed for the self-consistent evaluation of Hubbard parameters [3]. 
I will show how this formalism can be used for the evaluation of such 
properties as voltages in Li-ion batteries, formation energies of oxygen 
vacancies in perovskites, and I will discuss the applicability of this 
formalism for improving band gaps with respect to standard DFT [5] and 
its use for searching of novel materials for the photocatalytic water 
splitting [6].  Finally, I will present the extension of this framework 
to the calculations of phonons [7] and electron-phonon coupling [8] in 
selected transition-metal compounds. These tools are implemented in the 
open-source Quantum ESPRESSO distribution [9] and are available to the 
community at large.



[1] V.L. Campo Jr and M. Cococcioni, J. Phys.: Condens. Matter. 22, 
055602 (2010).
[2] I. Timrov, N. Marzari, M. Cococcioni, Phys. Rev. B 98, 085127 (2018).
[3] I. Timrov, N. Marzari, M. Cococcioni, Phys. Rev. B 103, 045141 (2021).
[4] I. Timrov, F. Aquilante, L. Binci, M. Cococcioni, N. Marzari, Phys. 
Rev. B 102, 235159 (2020).
[5] N.E. Kirchner-Hall, W. Zhao, Y. Xiong, I. Timrov, I. Dabo, Appl, 
Sci. 11, 2395 (2021).
[6] Y. Xiong et al., Energy Environ. Sci. 14, 2335 (2021).
[7] A. Floris, I. Timrov, B. Himmetoglu, N. Marzari, S. de Gironcoli, M. 
Cococcioni, Phys. Rev. B 101, 064305 (2020).
[8] J.-J. Zhou, J. Park, I. Timrov, A. Floris, M. Cococcioni, N. 
Marzari, M. Bernardi, Phys. Rev. Lett. 127, 126404 (2021).
[9] P. Giannozzi et al., J. Phys.: Condens. Matter 29, 465901 (2017).


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CMSP, Condensed Matter & Statistical Physics Section
http://www.ictp.it/research/cmsp.aspx

The Abdus Salam International Centre for Theoretical Physics
https://www.ictp.it/

    
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